Modular electric assist system for bicycles

Abstract

This invention provides a modular electric assist system for bicycles, including a transmission unit module comprising a mounting part and a transmission part. The mounting part of the transmission unit module is used to detachably mount the transmission unit module at the bottom bracket of the frame. The transmission part includes a bottom bracket axle (BB axle) and a chainring. The BB axle passes through the bottom bracket of the frame, and the chainring is driven on one side of the bottom bracket and is connected to the BB axle. A drive unit module is detachably mounted on the transmission unit module and is connected to the transmission part of the transmission unit module. Through the detachable transmission unit module and the detachable drive unit module, an electric assist system can be installed on a conventional bicycle, enabling electric modification of commercially available bicycles without requiring a special frame structure. It is highly adaptable, and by combining different models of transmission unit modules and drive unit modules, it is easy to operate, low in cost, and highly flexible in use.

Description

Technical Field

[0001] This invention relates to the field of electric-assisted bicycle technology, and more specifically, to a modular electric-assisted system for bicycles. Background Technology

[0002] Currently, electric-assist bicycles on the market are mainly divided into hub motor models and mid-drive motor models. Structurally speaking, mid-drive motor models have higher torque, better riding experience, and better market prospects. However, due to price issues, they have only gradually entered the domestic market in recent years.

[0003] Due to varying market demands, manufacturers often need to launch different products, resulting in a wide variety of product specifications on the market. For example, there are different power ratings, different voltage inputs, different operating conditions, and different vehicle models. Different products require different targeted design solutions. Furthermore, conventional mid-drive motor models often require special frame designs and are generally more expensive.

[0004] A Chinese patent application with publication number CN117325974B discloses a highly stable mid-drive electric-assisted mountain bike, comprising a frame, axles, wheels, a housing, a mid-drive motor, a bottom bracket, and pedals; the frame is rotatably connected to several axles; each axle is fixedly connected to a wheel; the frame is fixedly connected to a housing; the housing houses the mid-drive motor; the output shaft of the mid-drive motor is fixedly connected to the bottom bracket, and the bottom bracket passes through the mid-drive motor and is rotatably connected to the housing; the bottom bracket is spun to several pedals.

[0005] Existing electric-assist bicycles integrate the mid-mounted motor into the frame, requiring a special frame structure. However, the majority of bicycles on the market are still ordinary bicycles, and existing electric-assist solutions cannot be flexibly used on ordinary bicycle frames, thus requiring improvement. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the purpose of this invention is to provide a modular electric assist system for bicycles.

[0007] According to the present invention, a modular electric assist system for bicycles includes a transmission unit module and a drive unit module. The transmission unit module includes a mounting part and a transmission part. The mounting part of the transmission unit module is used to detachably mount the transmission unit module at the bottom bracket of the frame. The transmission part includes a bottom bracket axle (BB axle) and a chainring. The BB axle passes through the bottom bracket of the frame, and the chainring is driven and mounted on one side of the bottom bracket of the frame, and the chainring is driven and connected to the BB axle. The drive unit module is detachably mounted on the transmission unit module, and the drive unit module is driven and connected to the transmission part of the transmission unit module.

[0008] Preferably, the mounting portion of the transmission unit module includes a transmission unit housing, which includes a main body and a mounting shaft. The main body is located at one end of the mounting shaft. The end of the mounting shaft away from the main body passes through one end of the frame bottom bracket and exits at the other end. An auxiliary bracket is connected to the end of the mounting shaft away from the main body. The auxiliary bracket extends to the main body and is detachably connected to the main body via fasteners. The end of the mounting shaft away from the main body is threadedly engaged with a locking nut. The locking nut and the auxiliary bracket engage to detachably connect the transmission unit housing to the frame bottom bracket.

[0009] Preferably, the transmission unit further includes a concave claw-shaped gear shaft, a transmission gear set, and a clutch assembly, all of which are mounted on the mounting part of the transmission unit module. The concave claw-shaped gear shaft is detachably connected to the output shaft of the drive unit module, and is connected to the crankshaft via the transmission gear set and the clutch assembly. The BB shaft is connected to the crankshaft via the clutch assembly.

[0010] Preferably, the clutch assembly includes a gear clutch, a clutch body, and a clutch liner. The clutch liner is fixedly connected to the BB shaft. The clutch body is sleeved on the outer circle of the clutch liner. The gear clutch is sleeved on the clutch body. The sprocket is fixedly connected to the outer circle of the gear clutch.

[0011] Preferably, the transmission gear set includes a transmission gear shaft and a transmission gear, the transmission gear shaft and the transmission gear are fixedly connected, the concave claw-shaped gear shaft meshes with the transmission gear, and the transmission gear shaft meshes with the teeth of the gear clutch.

[0012] Preferably, the BB shaft coaxially passes through the gear clutch, and the BB shaft rotates with the gear clutch through a bearing.

[0013] Preferably, the mounting portion of the transmission unit module is provided with a mounting point for the drive unit module, and the drive unit module is detachably connected to the mounting point of the transmission unit module mounting portion via fasteners;

[0014] The output shaft of the drive unit module is a claw-shaped external spline motor shaft, which is mated with a concave claw-shaped toothed shaft.

[0015] Preferably, the drive unit module mounting point on the mounting part of the transmission unit module is located in the middle or lower part of the bottom bracket of the frame.

[0016] Preferably, the output voltage of the drive unit module includes 24V, 36V or 48V.

[0017] Preferably, the drive unit module integrates a control system, or the drive unit module is electrically connected to an external control system.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. This invention enables the installation of an electric assist system on a conventional bicycle by using a transmission unit module that can be detachably connected to the bottom bracket of the frame, and a drive unit module that can be detachably connected to the transmission unit module. This allows for the electric modification of commercially available bicycles without requiring a special frame structure, making it highly adaptable. Furthermore, different models of transmission unit modules and drive unit modules can be combined, making operation convenient, cost-effective, and highly flexible.

[0020] 2. This invention uses an auxiliary bracket and a locking nut to install the transmission unit module at the bottom bracket of the vehicle frame. By using a modular motor, there is no need to disassemble the transmission unit module related to the vehicle frame. Only the drive unit module that is compatible with it needs to be replaced. The drive unit solutions offer higher power, high torque at low speed, and uniform speed energy saving, with diverse configuration options, which can reduce travel costs without replacing the entire machine. Attached Figure Description

[0021] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0022] Figure 1 This is an exploded view of the modular electric assist system, which is the main feature of this invention.

[0023] Figure 2 This is an exploded view of the installation structure of the transmission unit module, which is the main feature of this invention.

[0024] Figure 3 This is an exploded view showing the installation structure of the transmission unit module on the bottom bracket of the vehicle frame, which is the main feature of this invention.

[0025] Figure 4 This is a schematic diagram illustrating the overall structure of the transmission unit module, which is the main feature of this invention.

[0026] Figure 5 This is a schematic diagram illustrating the structure of the transmission unit module mounting section, which is the main feature of this invention.

[0027] Figure 6 This is a schematic diagram illustrating the structure of the transmission unit module of the present invention.

[0028] Figure 7 This is a schematic diagram illustrating the overall structure of the drive unit module, which is the main feature of this invention.

[0029] Figure 8This is an exploded view illustrating the overall structure of the drive unit module, which is the main feature of this invention.

[0030] As shown in the figure:

[0031] Transmission unit module 1, clutch body 13

[0032] Drive unit module 2 Clutch liner 14

[0033] Frame 3, BB axle 15

[0034] Concave claw-shaped gear shaft 5; Transmission gear shaft 16

[0035] Auxiliary support 6, transmission gear 17

[0036] Locking nut 7, claw-type external spline motor shaft 18

[0037] Mounting screws 8, drive unit stator 19

[0038] Transmission unit housing 9 Drive unit screws 20

[0039] Transmission unit cover 10 Drive unit cover 21

[0040] Crank 11 Drive unit rotor 22

[0041] Gear clutch 12 Drive unit housing 23 Detailed Implementation

[0042] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0043] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 as well as Figure 8As shown, a modular electric assist system for bicycles according to the present invention includes a transmission unit module 1 and a drive unit module 2. The transmission unit module 1 includes a mounting part and a transmission part. The mounting part of the transmission unit module 1 is used to detachably mount the transmission unit module 1 at the bottom bracket of the frame 3. The transmission part includes a bottom bracket axle 15 and a chainring 11. The bottom bracket axle 15 passes through the bottom bracket of the frame 3, and the chainring 11 is drivenly mounted on one side of the bottom bracket of the frame 3 and is drivenly connected to the bottom bracket axle 15. The drive unit module 2 is detachably mounted on the transmission unit module 1, and the drive unit module 2 is drivenly connected to the transmission part of the transmission unit module 1.

[0044] This application's technical solution utilizes a transmission unit module 1 that can be detachably connected to the bottom bracket of the frame 3, and a drive unit module 2 that can be detachably connected to the transmission unit module 1. This enables the installation of an electric assist system on a conventional bicycle, achieving electric modification of commercially available bicycles without requiring a special frame 3 structure, thus offering strong applicability. Furthermore, different models of transmission unit modules 1 and drive unit modules 2 can be combined, making operation convenient, cost-effective, and highly flexible in use.

[0045] Specifically, the mounting portion of the transmission unit module 1 includes a transmission unit housing 9. The transmission unit housing 9 includes a main body and a mounting shaft. The main body is located at one end of the mounting shaft. The end of the mounting shaft away from the main body passes through one end of the bottom bracket of the frame 3 and exits at the other end. An auxiliary bracket 6 is connected to the end of the mounting shaft away from the main body. The auxiliary bracket 6 extends to the main body and is detachably connected to the main body via fasteners. The end of the mounting shaft away from the main body is threadedly engaged with a locking nut 7. The locking nut 7 and the auxiliary bracket 6 cooperate to detachably connect the transmission unit housing 9 to the bottom bracket of the frame 3. Further, in a feasible embodiment: the auxiliary bracket 6 includes an integrally formed annular portion, an intermediate connecting portion, and an end mounting portion. The annular portion is located at one end of the intermediate connecting portion, and the end mounting portion is located at the other end of the intermediate connecting portion. The annular portion is sleeved on the end of the mounting shaft away from the main body. The intermediate connecting portion extends axially along the bottom bracket of the frame 3 outside the bottom bracket. The end mounting portion is fixedly connected to the main body of the transmission unit housing 9 via mounting screws 8. The end of the mounting shaft away from the main body is threaded, and the locking nut 7 is threaded to the end of the mounting shaft away from the main body. The locking nut 7 also presses the annular part of the auxiliary bracket 6 onto the end face of the bottom bracket of the frame 3. This achieves a detachable connection of the transmission unit module 1 to the frame 3.

[0046] More specifically, the transmission unit also includes a concave claw-shaped gear shaft 5, a set of 17 transmission gears, and a clutch assembly. The concave claw-shaped gear shaft 5, the set of 17 transmission gears, and the clutch assembly are all mounted on the mounting section of the transmission unit module 1. The concave claw-shaped gear shaft 5 is detachably connected to the output shaft of the drive unit module 2. The concave claw-shaped gear shaft 5 is connected to the chainring 11 via the set of 17 transmission gears and the clutch assembly. The BB shaft 15 is connected to the chainring 11 via the clutch assembly. The user can rotate the BB shaft 15 by pedaling, which in turn rotates the chainring 11 via the clutch assembly to perform riding. The motor can provide riding assistance by rotating the chainring 11 via the set of 17 transmission gears and the clutch assembly.

[0047] More specifically, in a preferred embodiment, the clutch assembly includes a gear clutch 12, a clutch body 13, and a clutch liner 14. The clutch liner 14 is fixedly connected to the BB shaft 15. The clutch body 13 is sleeved on the outer circle of the clutch liner 14, and the gear clutch 12 is sleeved on the clutch body 13. The gear sprocket 11 is fixedly connected to the outer circle of the gear clutch 12. The clutch liner 14 and the clutch body 13 form a wedge clutch. The wedge clutch, in conjunction with the gear clutch 12, forms a dual-clutch system, ensuring that the BB shaft 15 will not jam when rotating in either the forward or reverse direction. The transmission gear 17 group includes a transmission gear shaft 16 and a transmission gear 17, which are coaxially fixedly connected. A concave claw-shaped gear shaft 5 meshes with the transmission gear 17, and the transmission gear shaft 16 meshes with the teeth of the gear clutch 12. The BB shaft 15 coaxially passes through the gear clutch 12, and the BB shaft 15 is rotatably engaged with the gear clutch 12 through bearings.

[0048] It should be noted that the concave claw-shaped gear shaft 5, the transmission gear set 17, and the clutch assembly are all located in the main body of the transmission unit housing 9. The sprocket 11 is located on the side of the main body of the transmission unit housing 9 away from the mounting shaft, and there is a fitting clearance between the sprocket 11 and the main body of the transmission unit housing 9 to ensure the stability of the sprocket 11's rotation. The BB shaft 15 is rotatably connected to the inner cavity of the gear clutch 12 through a bearing, and the BB shaft 15 is also rotatably connected to the inner cavity of the mounting shaft of the transmission unit housing 9 through a bearing, thus achieving stable installation of the BB shaft 15.

[0049] The technical solution of this application uses a dual-clutch system to ensure that the rotation of the BB shaft 15 does not interfere with the motor's assistance, and to prevent the BB shaft 15 from jamming when rotating forward or in reverse.

[0050] Furthermore, the mounting portion of the transmission unit module 1 is provided with mounting points for the drive unit module 2. The drive unit module 2 is detachably connected to the mounting points of the transmission unit module 1 via fasteners. The output shaft of the drive unit module 2 is a claw-shaped external spline motor shaft 18, which mates with a concave claw-shaped gear shaft 5. Thanks to the detachable mounting method of the drive unit module 2 and the transmission unit module 1, and the mating of the claw-shaped external spline motor shaft 18 and the concave claw-shaped gear shaft 5, the transmission unit module 1 can be installed onto the frame 3 first, and then different drive unit modules 2 can be installed according to requirements. For example, the output voltage of the drive unit module 2 can be 24V, 36V, or 48V; the drive unit module 2 with the corresponding output voltage can be selected according to requirements. This forms a modular design approach. A transmission unit cover plate 10 is mounted on the side of the transmission unit housing 9 away from the crankset 11.

[0051] In one alternative implementation, the transmission unit module 1 and the drive unit module 2 are connected to a coupling via a concave claw-shaped gear shaft 5 to realize the transmission of power from the drive unit to the transmission unit.

[0052] In one feasible implementation: the drive unit module 2 includes a drive unit stator 19, drive unit screws 20, a drive unit cover plate 21, a drive unit rotor 22, and a drive unit housing 23; the drive unit housing 23 is fixedly connected to the drive unit module 2 mounting point of the mounting part of the transmission unit module 1 via the drive unit screws 20; the drive unit stator 19 and the drive unit rotor 22 are disposed inside the drive unit housing 23; and the drive unit cover plate 21 is fixedly connected to the drive unit housing 23. A claw-shaped external spline motor shaft 18 is fixedly connected to the drive unit rotor 22, and the claw-shaped external spline motor shaft 18 extends from inside the drive unit housing 23, serving as the output shaft of the drive unit module 2.

[0053] In a preferred embodiment: the mounting point of the drive unit module 2 on the mounting part of the transmission unit module 1 is located in the middle or lower part of the bottom bracket of the frame 3.

[0054] During installation, the transmission unit module 1 is first inserted into the bottom bracket of the bicycle. At this point, the transmission unit and frame 3 form a fixed structure, which can be considered as a whole. The deceleration system of the electric-assist bicycle is now assembled. The drive unit module 2 is then assembled with the transmission unit module 1 using screws, forming a complete set of products. When needs are adjusted, different modules can be used to address these issues. The transmission unit and drive unit systems are designed as separate modular solutions, allowing for partial replacements during installation to meet different requirements and scenarios.

[0055] Specifically, the transmission unit module 1 is first initially installed on the bottom bracket of the frame 3, then the auxiliary bracket 6 is installed on the transmission unit module 1, and the auxiliary bracket 6 is fastened to the transmission unit module 1 with screws. Then, the transmission unit module 1 passing through the bottom bracket of the frame 3 is fastened with the locking nut 7. At this time, the transmission unit module 1 has been firmly combined with the frame 3 to form a whole; at this time, the transmission unit module 1 has been assembled.

[0056] Without drive unit module 2, the bicycle currently cannot provide electric assist. Drive unit module 2 needs to be installed later based on the requirements of the entire system. For example, if the bicycle uses a 24V system (it could also be 36V or 48V, etc.), then the 24V drive unit module 2 will be initially assembled using the claw-type external spline motor shaft 18 and the concave claw-type gear shaft 5 (a part of the transmission unit). Then, it will be fastened to the transmission unit module 1 using drive unit screws 20. At this point, the modular motor is assembled. Regardless of whether the customer chooses a 36V or 48V system later, transmission unit module 1 does not need to be disassembled; only drive unit module 2 needs to be replaced. Afterward, the left and right cranks and pedals will be installed to complete the system connection.

[0057] It should be noted that the drive unit module 2 integrates a control system, or the drive unit module 2 is electrically connected to an external control system.

[0058] Furthermore, for consumers, this technical solution simplifies selection and reduces costs. If a consumer needs a mid-drive motor for long-distance travel, short-distance urban commuting, or certain off-road requirements, they no longer need to purchase two or three separate mid-drive motors for reinstallation, as is common in the current market. Using this modular motor eliminates the need to disassemble the transmission unit module 1 associated with the frame 3; only the compatible drive unit module 2 needs to be replaced. This offers a variety of drive unit options, including higher power, low-speed high torque, and energy-saving constant-speed operation. Given the generally higher price of these products, this solution reduces travel costs, eliminating the need for a complete replacement. For manufacturers, the technical solution reduces costs. During production, the transmission unit manufacturing process is not constrained by the drive unit, and vice versa. Unlike traditional manufacturing processes where material shortages prevent production, the transmission and drive units are stocked and assembled separately. This streamlined inventory management significantly improves production efficiency and facilitates after-sales maintenance.

[0059] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0060] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A modular electric assist system for a bicycle, characterized in that, The system includes a transmission unit module and a drive unit module. The transmission unit module includes a mounting part and a transmission part. The mounting part of the transmission unit module is used to detachably install the transmission unit module at the bottom bracket of the frame. The transmission part includes a BB shaft and a chainring. The BB shaft passes through the bottom bracket of the frame. The chainring is driven and installed on one side of the bottom bracket of the frame, and the chainring is driven and connected to the BB shaft. The drive unit module is detachably mounted on the transmission unit module, and the drive unit module is connected to the transmission part of the transmission unit module. The mounting part of the transmission unit module includes a transmission unit housing, which includes a main body and a mounting shaft. The main body is located at one end of the mounting shaft, and the end of the mounting shaft away from the main body passes through one end of the frame bottom bracket and exits at the other end. An auxiliary bracket is connected to the end of the mounting shaft away from the main body. The auxiliary bracket extends to the main body and is detachably connected to the main body via fasteners. The end of the mounting shaft away from the main body is threadedly engaged with a locking nut. The locking nut and the auxiliary bracket engage to detachably connect the transmission unit housing to the frame bottom bracket. The mounting part of the transmission unit module is provided with a mounting point for the drive unit module, and the drive unit module is detachably connected to the mounting point of the transmission unit module mounting part by fasteners; The transmission unit also includes a concave claw-shaped gear shaft, a transmission gear set, and a clutch assembly, all of which are assembled in the mounting part of the transmission unit module. The concave claw-shaped gear shaft is detachably connected to the output shaft of the drive unit module. The concave claw-shaped gear shaft is connected to the crankshaft via a transmission gear set and a clutch assembly. The BB shaft is connected to the crankshaft via a clutch assembly. The auxiliary bracket includes an integrally formed annular portion, an intermediate connecting portion, and an end mounting portion. The annular portion is located at one end of the intermediate connecting portion, and the end mounting portion is located at the other end of the intermediate connecting portion. The annular portion is sleeved on the end of the mounting shaft portion away from the main body portion. The intermediate connecting portion extends axially along the bottom bracket of the frame outside the bottom bracket. The end mounting portion is fixedly connected to the main body portion of the transmission unit housing by mounting screws. The end of the mounting shaft portion away from the main body portion is provided with threads. A locking nut is threadedly connected to the end of the mounting shaft portion away from the main body portion, and the locking nut presses the annular portion of the auxiliary bracket onto the end face of the bottom bracket of the frame.

2. Modular electric assistance system for a bicycle according to claim 1, characterized in that, The clutch assembly includes a gear clutch, a clutch body, and a clutch liner. The clutch liner is fixedly connected to the BB shaft. The clutch body is sleeved on the outer circle of the clutch liner. The gear clutch is sleeved on the clutch body. The sprocket is fixedly connected to the outer circle of the gear clutch.

3. The modular electric assist system for bicycles as described in claim 2, characterized in that, The transmission gear set includes a transmission gear shaft and a transmission gear, which are fixedly connected. The concave claw-shaped gear shaft meshes with the transmission gear, and the transmission gear shaft meshes with the teeth of a gear clutch.

4. The modular electric assist system for bicycles as described in claim 1, characterized in that, The BB shaft coaxially passes through the gear clutch, and the BB shaft rotates with the gear clutch through bearings.

5. The modular electric assist system for bicycles as described in claim 1, characterized in that, The output shaft of the drive unit module is a claw-shaped external spline motor shaft, which is mated with a concave claw-shaped toothed shaft.

6. The modular electric assist system for bicycles as described in claim 1, characterized in that, The drive unit module mounting point on the mounting part of the transmission unit module is located in the middle or lower part of the bottom bracket of the frame.

7. The modular electric assist system for bicycles as described in claim 1, characterized in that, The output voltage of the drive unit module includes 24V, 36V or 48V.

8. The modular electric assist system for bicycles as described in claim 1, characterized in that, The drive unit module integrates a control system, or the drive unit module is electrically connected to an external control system.

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